QSEST call Proxy or Engine?

[DataWrangler]

Could anyone please advise: do the QSEST (Qlik Sense Enterprise Scalability Tools)

1. Generate web sockets traffic against the Qlik Sense Proxy service? (top half of screen shot)
   OR
2. Generate API calles directly to the Qlik Sense Engine service?  (bottom half of screen shot)

And as a follow-up question, do the legacy QSST operate against the Proxy or the Engine?

Thanks,

JR